/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "jit/ShapeList.h"

#include "gc/GC.h"

#include "vm/List-inl.h"

using namespace js;
using namespace js::jit;

const JSClass ShapeListObject::class_ = {
    "JIT ShapeList",
    0,
    &classOps_,
};

const JSClassOps ShapeListObject::classOps_ = {
    nullptr,                 // addProperty
    nullptr,                 // delProperty
    nullptr,                 // enumerate
    nullptr,                 // newEnumerate
    nullptr,                 // resolve
    nullptr,                 // mayResolve
    nullptr,                 // finalize
    nullptr,                 // call
    nullptr,                 // construct
    ShapeListObject::trace,  // trace
};

/* static */ ShapeListObject* ShapeListObject::create(JSContext* cx) {
  NativeObject* obj = NewTenuredObjectWithGivenProto(cx, &class_, nullptr);
  if (!obj) {
    return nullptr;
  }

  // Register this object so the GC can sweep its weak pointers.
  if (!cx->zone()->registerObjectWithWeakPointers(obj)) {
    ReportOutOfMemory(cx);
    return nullptr;
  }

  return &obj->as<ShapeListObject>();
}

Shape* ShapeListObject::get(uint32_t index) const {
  Shape* shape = getUnbarriered(index);
  gc::ReadBarrier(shape);
  return shape;
}

Shape* ShapeListObject::getUnbarriered(uint32_t index) const {
  Value value = ListObject::get(index);
  return static_cast<Shape*>(value.toPrivate());
}

void ShapeListObject::trace(JSTracer* trc, JSObject* obj) {
  if (trc->traceWeakEdges()) {
    obj->as<ShapeListObject>().traceWeak(trc);
  }
}

bool ShapeListObject::traceWeak(JSTracer* trc) {
  uint32_t length = getDenseInitializedLength();
  if (length == 0) {
    return false;  // Object may be uninitialized.
  }

  const HeapSlot* src = elements_;
  const HeapSlot* end = src + length;
  HeapSlot* dst = elements_;
  while (src != end) {
    Shape* shape = static_cast<Shape*>(src->toPrivate());
    MOZ_ASSERT(shape->is<Shape>());
    if (TraceManuallyBarrieredWeakEdge(trc, &shape, "ShapeListObject shape")) {
      dst->unbarrieredSet(PrivateValue(shape));
      dst++;
    }
    src++;
  }

  MOZ_ASSERT(dst <= end);
  uint32_t newLength = dst - elements_;
  setDenseInitializedLength(newLength);

  if (length != newLength) {
    JitSpew(JitSpew_StubFolding, "Cleared %u/%u shapes from %p",
            length - newLength, length, this);
  }

  return length != 0;
}